Biggest Change Fueling San Francisco 49ers’ Defensive Success Revealed

NEW ORLEANS, LOUISIANA – SEPTEMBER 14: Nick Bosa #97 of the San Francisco 49ers celebrates a sack against the New Orleans Saints during the second half in the game at Caesars Superdome on September 14, 2025 in New Orleans, Louisiana. (Photo by Sean Gardner/Getty Images)

Especially considering the litany of injuries the team has had to endure, the San Francisco 49ers’ 2-0 start to the season has been a massive success.

But beyond just the result, a big reason why 49ers fans are feeling confident about the season ahead is because of the defensive performance.

Heading into the season, many fans figured the defense would struggle. The 49ers lost several key players on defense via free agency, and many starters and other key contributors are rookies or otherwise inexperienced players.

But instead, the 49ers defense has been one of the best in the NFL throughout the first two weeks. They have allowed only 17 points per game and 268.5 yards per game. They have also managed to come up with three takeaways.

But according to superstar 49ers defensive end Nick Bosa, there is one big reason why this season feels much better on the defensive side of the ball.

“In the past, it seems like we’d find a way to lose,” Bosa said (h/t ESPN). “And two games like this — dog fights to start the year and just closing it on defense — there’s no better feeling.”

Essentially, Bosa said the 49ers’ improved play in the clutch is the main thing helping them win games.

How Much Did the 49ers Struggle In The Clutch Last Season?

Every 49ers fan unfortunately remembers San Francisco’s 6-11 record last season.

But what they may not know is how much bad clutch defensive play was the reason for those losses.

The 49ers tied or were outscored in the fourth quarter in 10 of their 11 losses. In addition, over half of their losses (6 of 11) were by a touchdown (7 points) or less.

Time after time, the 49ers blew a fourth quarter lead and the season flew further off the rails.

In addition, the 49ers had the second-worst red zone defense in the NFL. They allowed a touchdown on 68.4% of opponent trips to the red zone. Only the Dallas Cowboys were worse.

The 49ers defense wasn’t good by any metric last season, but they were decent throughout most of the game, for most of the season. They were just especially terrible in the most key moments.

49ers Defense Clutch So Far In 2025

Perhaps the return of Robert Saleh is somehow making the 49ers more confident in the clutch.

The red zone defense still isn’t great. The 49ers are still in the bottom half of the NFL (20th) in red zone defense.

But, in the closing moments of the fourth quarter, the 49ers defense has come up huge.

In Week 1, a strip sack by Nick Bosa on Seattle Seahawks quarterback Sam Darnold in the final seconds of the game secured the victory for San Francisco.

In Week 2, it was defensive end Bryce Huff that got a strip sack on New Orleans Saints QB Spencer Rattler on fourth down to secure the win for the Niners.

Both plays came with the 49ers leading by less than a touchdown, and the opponent leading a last-gasp drive to try and win the game.

And sure enough, the 49ers haven’t been outscored in the fourth quarter yet this season.

If the 49ers “closers”, as Robert Saleh likes to call them, like Nick Bosa, Bryce Huff and linebacker Fred Warner continue to make the necessary plays in the biggest moments, the 49ers can quickly pivot from a 6-11 season to a playoff season.

What have you thought about the defense so far this season, 49ers fans?

Ethan Inman is a sports journalist covering the San Francisco 49ers, San Francisco Giants and Las Vegas Raiders for heavy.com. He also co-hosts a college football podcast for The Voice of College Football, and writes about the NBA and MLB. He has previously covered the USC Trojans, the NHL, college baseball, and the intersection of sports and popular culture for other publications. He is based in the greater Los Angeles area. More about Ethan Inman